Practical Training SeminarPPT onGSM Systems Presented By: Presented to : Jaideep Singh Er. Vidhi Vrat 12EAIEC066 Er. Nemi Chand ECE-A (Seminar Coordinator )

COMPANY OVERVIEW

Nokia Siemens Networks (N.S.N) is a multinational data networking and telecommunications equipment company headquartered at Espoo, Finland and wholly owned subsidiary of Nokia corporation. It started as a joint venture between Nokia of Finland and Siemens of Germany in 2007. NSN acquired Atrica and Apertio which helped it gain customers in the subscribers management area including Orange, T-Mobile, O2 , Vodafone and Hutchison 3G.In 2011, NSN completed its acquisition of wireless-network equipment division of Motorola for $975 million in cash.Page *

Basic idea of GSM system Features of GSMThe structure of the GSM system.Certain numbers that refer to BSS Handovers, frequency hopping and location updatesThe idea of EDGE and GPRSPage *

GSM system overviewThe Global System for Mobile Communications (GSM) is a set of recommendations and specifications for a digital cellular telephone network (known as a Public Land Mobile Network, or PLMN). These recommendations ensure the compatibility of equipment from different GSM manufacturers, and interconnectivity between different administrations, including operation across international boundaries. GSM networks are digital and can cater for high system capacities. They are consistent with the world-wide digitization of the telephone network, and are an extension of the Integrated Services Digital Network (ISDN), using a digital radio interface between the cellular network and the mobile subscriber equipment. Page *

Page *Standard Protocol for GSM take effectSystem was named as Global System for Mobile Communication GSM system began to provide service in Europe(2G)Provide services for the whole worldMicro Cell Technique is used in GSM system19891991199219941996GSM History and Overview

A certain radio coverage area formed by a set of transceivers that connected to a set of antennas is called a CELL.Macro Cell In the beginning , High-Power BTSs are adopted to provide services. The BTS covers a wider area , but its frequency utilization is not efficient. So , it can only provide a few channels for subscribers.Micro Cell Later the Low-Power BTS joins the system for getting a better service area with high capacity . At the same time it adopts the frequency reuse technique to improve the efficiency of the frequency utilization and also the whole capacity of the network.Page *Macro Cell and Micro CellCell Definitions

Multiple Access Technique allows many subscribers to use the same communication medium.There are three kinds of basic Multiple Access Technique : 1) FDMA2) TDMA and 3) CDMA.GSM system adopt FDD-TDMA (FDMA and TDMA together).

Page *Multiple Access Technique

Page *GSM 900 GSM systems use radio frequencies between 890-915 MHz for receive and between 935-960 MHz for transmit.RF carriers are spaced every 200 kHz, allowing a total of 124 carriers for use.An RF carrier is a pair of radio frequencies, one used in each direction.Transmit and receive frequencies are always separated by 45 MHz.Frequency Spectrum

Page *INCREASED CAPACITYThe GSM system provides a greater subscriber capacity than analogue systems.GSM allows 25 kHz per user, that is, eight conversations per 200 kHz channel pair (a pair comprising one transmit channel and one receive channel).

IMPROVED SECURITY AND CONFIDENTIALITY The mobile has an identity number hard coded into it when it is manufactured. This number is stored in a standard database and whenever a call is made the equipment can be checked to see if it has been reported stolen.

Features of GSM

Page *

ENHANCED RANGE OF SERVICESSpeech services for normal telephony.Short Message Service for point to point transmission of text message.Cell broadcast for transmission of text message from the cell to all MS in its coverage area. Message like traffic information or advertising can be transmitted.Fax and data services are provided. Data rates available are 2.4 Kb/s, 4.8 Kb/s and 9.6 Kb/s.Supplementary services like number identification , call barring, call forwarding, charging display etc can be provided.Features of GSM

Page *GSM /GPRS BSSBTSBSCBTSBSCPCUSS7SMS systemPSTNISDNInternet,IntranetMSC/VLRGMSCHLR/AUCSGSNCGBGGGSNGPRS backboneOther PLMNAGbGiGpC/D/GsGr/Gs/Gd/GeGcGaAbisUmMSMSOMCInterface Between Different Entities

Mobile StationMSPage *

An MS is used by a mobile subscriber to communicate with the mobile network. Several types of MSs exist, each allowing the subscriber to make and receive calls.The range or coverage area of an MS depends on the output power of the output. Different types of MSs have different output power capabilities and consequently different ranges.GSM MSs consist ofA mobile terminalA Subscriber Identity Module (SIM)In GSM the subscriber is separated from the mobile terminal. Each subscribers information is stored as a smart card SIM. The SIM can be plugged into any GSM mobile terminal. This brings the advantages of security and portability of subscribers.

Page *The BSS is the fixed end of the radio interface that provides control and radio coverage functions for one or more cells and their associated MSs.It is the interface between the MS and the MSC.The BSS comprises one or more Base Transceiver Stations (BTSs), each containing the radio components that communicate with MSs in a given area, and a Base Site Controller (BSC) which supports call processing functions and the interfaces to the MSC. Digital radio techniques are used for the radio communications link, known as the Air Interface, between the BSS and the MS. The BSS consists of three basic Network Elements (NEs). Transcoder (XCDR) or Remote transcoder (RXCDR) .Base Station Controller (BSC). Base Transceiver Stations (BTSs) assigned to the BSC.

Base Station Subsystem-BSS

Page *30 Timeslots1 traffic channel / TS64 Kbps / TS4 E1 lines = 30 X 4=120 TimeslotsEach Timeslot =16 X 4 = 64 Kb/s30 timeslots = 30 x 4=120 traffic channelsMSCXCDRBSC0123116Transcoded information from four callsTranscoder

Page *

The BSC network element provides the control for the BSS. It controls and manages the associated BTSs, and interfaces with the Operations and Maintenance Centre (OMC). The purpose of the BSC is to perform a variety of functions. The following comprise the functions provided by the BSC:Controls the BTS components.-Performs Call Processing. Performs Operations and Maintenance (O & M). Provides the O & M link (OML) between the BSS and the OMC. Provides the A Interface between the BSS and the MSC. Manages the radio channels. Transfers signaling information to and from MSs.

Base Station Controller-BSC

Page *

The BTS network element consists of the hardware components, such as radios, interface modules and antenna systems that provide the Air Interface between the BSS and the MSs. The BTS provides radio channels (RF carriers) for a specific RF coverage area.The radio channel is the communication link between the MSs within an RF coverage area and the BSS.The BTS also has a limited amount of control functionality which reduces the amount of traffic between the BTS and BSC.

Base Tran receiver Station-BTS

IMEIPage *IMEI: International Mobile Station Equipment IdentificationTAC: Type approval code, 6 bit, determined by the type approval centerFAC: Final assembly code, 2 bit, It is determined by the manufacturer.SNR: Serial number, 6 bits, It is issued by the manufacturer of the MS. SP: 1 bit , Not used. Check the IMEI in your MS : *#06#

Page *The GSM handover process uses a mobile assisted technique for accurate and fast handovers, in order to: Maintain the user connection link quality. Manage traffic distributionThe overall handover process is implemented in the MS,BSS & MSC. Measurement of radio subsystem downlink performance and signal strengths received from surrounding cells, is made in the MS. These measurements are sent to the BSS for assessment. The BSS measures the uplink performance for the MS being served and also assesses the signal strength of interference on its idle traffic channels.Initial assessment of the measurements in conjunction with defined thresholds and handover strategy may be performed in the BSS. Assessment requiring measurement results from other BSS or other information resident in the MSC, may be perform. in the MSC.Handover

Page *Handover takes place in the same cell from one timeslot to another timeslot of the same carrier or different carriers( but the same cell).Intra-cell handover is triggered only if the cause is interference.Intra-cell handover can be enabled or disabled in a cell.

Intra-Cell HandoverBSCBTSCall is handed from timeslot 3 to timeslot 5

Sheet8

CLASSPOWER OUTPUT

120W

28W

35W

42W

50.8W

MSC

EC

01234567

PSTN

AUC HLR

EIR

VLR

NMC

OMC-S

OMC-R

IWF

XCDR

BTS

BTS

BSC

Cellular Technology Comparison

N Users / Wideband Channel

8 Users / Narrowband Channel

1

2

3

4

TDMA

200 kHz

Frequency

Time

1 User/ Narrowband Channel

FDMA

Frequency

Time

CDMA

1.23 MHz

Frequency

Time

CDMA Technology

Echo Broadband proprietary

T3109

MS

BSS

SACCH

LINK_FAIL EXCEEDEDDEACTIVATE D/L SACCHSTART TIMER T3109

SACCH NOT DECODED

START TIMER T100

SACCH DEACTIVATED ON D/L

T100 EXPIRES. RELEASE RADIO RESOURCES

TIMER T3109 STILL RUNNING

TIMER T3109 EXPIRESBSS RELEASES RADIO RESOURCE

waitindicati

100% TCH Usage

LWM

HWM

MS

CELL

RACH

IMMEDIATE ASSIGNMENTREJECT (AGCH)

NO SDCCH AVAILABLE

IF T3122 EXPIRES,MS CAN NOW SEND A FRESH REQUEST

SET T3122 IN MS EQUAL TO WAIT_INDICATION

RACH

INACTIVE MODE

Traffic Usage

Resource Indication to MSCNo Handover request entertained

Resource Indication to MSCHandover request entertained

No of TCH free

T3101

MS

CELL

RACH

CL2I

IF MS SENDS CL2I ON SDCCH STOP TIMER T3101

IMMEDIATE ASSIGNMENT(AGCH)

SDCCH ALLOCATED START TIMER T3101

MS

CELL

RACH

IMMEDIATE ASSIGNMENT(AGCH)

SDCCH ALLOCATED

START TIMER T3101

IF T3101 EXPIRES ANDBSS DOES NOT RECEIVECL2I ON SDCCH RELEASE ALLOCATED RESOURCES

Sheet7

FACTORSMACROMICROMULTILAYER

NUMBER OF SITES4(12 CELLS)24(24 CELLS)12+24 = 36

AREA CONSIDERED3.5 km23.5 km23.5 km2

NUMBER OF CARRIERS / CELL222

ERLANG / SUBSCRIBER25mE25mE25mE

GOS2%2%2%

ERLANGS / CELL FOR GIVEN GOS8.28.28.2

TOTAL ERLANGS GENERATED FOR GIVEN AREA98.4196.8295.2

NUMBER OF SUBSC SUPPORTED3936787211808

ERLANGS / km228.1156.2384.34

SPECTRUM AVAILABLE IN BOTH THE CASES IS 4.8MHZ

ERLANG B TABLE USED FOR CALCULATING ERLANGS FOR GIVEN GOS

Sheet1 (2)

BCCH

CCCH

BCCH

CCCH

CCCH

BCCH

CCCH

CCCH

CCCH

SACCH

SACCH

CCCH

CCCH

CCCH

CCCH

SDCCH

SDCCH

SDCCH

SDCCH

BCCH

CCCH

SDCCH

CCCH

SACCH

CCCH

SACCH

CCCH

CCCH

CCCH

SDCCH

CCCH

CCCH

CCCH

SDCCH

CCCH

CCCH

CCCH

SDCCH

BCCH

CCCH

A2

A3

BCCH

CCCH

A0

A1

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

D4

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

BCCH

CCCH

A6

A7

BCCH

CCCH

A4

A5

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

D4

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

BCCH

A0

BCCH

A4

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

D4

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

BCCH

CCCH

A2

A3

CCCH

A1

BCCH

CCCH

A6

A7

CCCH

A5

BCCH

AGCH

25

26

27

28

29

30

31

32

Sheet1

BCCH

CCCH

BCCH

CCCH

BCCH

CCCH

BCCH

CCCH

CCCH

CCCH

CCCH

CCCH

CCCH

CCCH

CCCH

CCCH

BCCH

CCCH

BCCH

CCCH

CCCH

BCCH

CCCH

CCCH

CCCH

SACCH

SACCH

CCCH

CCCH

CCCH

CCCH

SDCCH

SDCCH

SDCCH

SDCCH

BCCH

CCCH

SDCCH

CCCH

SACCH

CCCH

SACCH

CCCH

CCCH

CCCH

SDCCH

CCCH

CCCH

CCCH

SDCCH

CCCH

CCCH

CCCH

SDCCH

BCCH

CCCH

A2

A3

BCCH

CCCH

A0

A1

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

D4

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

BCCH

CCCH

A6

A7

BCCH

CCCH

A4

A5

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

D4

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

BCCH

A0

BCCH

A4

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

D4

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

CCCH

CCCH

CCCH

D7

CCCH

CCCH

CCCH

D6

CCCH

CCCH

CCCH

D5

CCCH

CCCH

CCCH

D4

CCCH

CCCH

CCCH

D3

CCCH

CCCH

CCCH

D2

CCCH

CCCH

CCCH

D1

CCCH

CCCH

CCCH

D0

BCCH

CCCH

A2

A3

CCCH

A1

BCCH

CCCH

A6

A7

CCCH

A5

Sheet4

System InformationBCCH Multiframe

10

21

32 and 6

43 and 7

124123122121cch_confPhysical ChannelsCombinedNo of CCH

016015014013012011010009

008007006005004003002001

87654321

Octet A

1111Octet BBCD

Octet C

Octet D

Octet E

87654321

Octet F

Octet G

cch_confPhysical ChannelsCombinedNo of CCHPaging TypeNo of MS using IMSINo of MS using TMSITotal no of MS

01 timeslot (0)NO912-287654321

11 timeslot (0)YES32123Octet 1

22 timeslots (0, 2)NO183-44Octet 2

43 timeslots (0, 2, 4)NO27

64 timeslots (0, 2, 4, 6)NO36

4Decoded

3Not Decoded

2

1

0

SACCH Blocks

COMBINEDCCCH BLOCKSAGCH BLOCKSPCH BLOCKS

No909

No918

No927

No936

No945

No954

No963

No972

Yes303

TX INTEGER RACH SLOTSS FOR NON-COMB CCCHS FOR COMB CCCHYes312

3, 8, 145541max_retransMtx_integerTYes321

4, 9, 1676521103

5, 10, 20109582214

6, 11, 25163863425

7, 12, 3212711547

1518

MCC DIG 1

MCC DIG 2

MCC DIG 3

MNC DIG 1

MNC DIG 2

LAC

LAC

Binary

CI

CI

Binary

Ordered MS Power Level

Spare

Ordered Timing Advance

Spare

t3105

HANDOVER COMMAND

START TIMER T3105

MS

TARGET CELL

SOURCE CELL

HANDOVER ACCESS

PHYSICAL INFORMATION

HANDOVER COMPLETE

IF HO COMPLETE MSGSTOP TIMER T3105

EXPIRED

EXPIRED

HANDOVER ACCESS

PHYSICAL INFORMATION

IF NO HO COMPLETE MSGAND T3105 EXPIRES SEND PHYSICAL INFO ANDSTART TIMER T3105

NY1 TIMES

HANDOVER FAILURE TO BSC

If NY1 = 0

Sheet6

HANDOVER COMMAND

HANDOVER FAILURE

START TIMER T3103

STOP TIMER T3103

MS

NETWORK

SOURCE CELL

INITIATE HANDOVER

UNSUCCESSFUL HANDOVER

HANDOVER COMPLETE

HANDOVER SUCCESSFUL

TARGET CELL

STOP TIMER T3103

EXPIRED

EXPIRED

Sheet5

POWER CONTROL RXQUAL

Only 2 N above threshold3 N above threshold

So no increase of powerSo Power is increased

by the MS

3 N below thresholdOnly 2 N below threshold

So power is decreased bySo no power is decreased

the BSSthe MS

POWER CONTROL RXQUAL

HANDOVER RXQUAL

-110 dBm

-100 dBm

-90 dBm

-80 dBm

-70 dBm

-47 dBm

-85 dBm

-75 dBm

0

10

20

30

40

63

l_rxlev_dl_p = 25

u_rxlev_dl_p = 35

l_rxlev_dl_p

u_rxlev_dl_p

-110 dBm

-47 dBm

-85 dBm

-75 dBm

0

63

l_rxlev_dl_p = 25

u_rxlev_dl_p = 35

Increase Power

Decrease Power

Do nothing

-60 dBm

N considered for power increase

N considered for power decrease

-110 dBm

-47 dBm

-90 dBm

-80 dBm

0

63

l_rxlev_ul_p = 20

u_rxlev_ul_p = 30

Increase Power

Decrease Power

Do nothing

-60 dBm

N considered for power increase

N considered for power decrease

-110 dBm

-90 dBm

-80 dBm

-47 dBm

-85 dBm

0

63

l_rxlev_ul_p = 20

u_rxlev_ul_p = 30

P1 out of N1Increase Power

P2 out of N2Decrease Power

-110 dBm

-100 dBm

-90 dBm

-80 dBm

-70 dBm

-47 dBm

-85 dBm

-75 dBm

0

10

20

30

40

63

l_rxlev_dl_p = 25

u_rxlev_dl_p = 35

0.14%

0

u_rxqual_ul_pu_rxqual_dl_p

2

3

4

6

7

0.57%

2.26%

9.05%

18.10%

1.13%

l_rxqual_ul_pl_rxqual_dl_p

P4 out of N4 decrease Power

P3 out of N3Increase Power

-110 dBm

-100 dBm

-90 dBm

-70 dBm

-47 dBm

0

10

20

30

40

63

0.14%

0

u_rxqual_ul_pu_rxqual_dl_p

2

4

6

7

0.57%

2.26%

9.05%

18.10%

l_rxqual_ul_pl_rxqual_dl_p

l_rxqual_ul_hl_rxqual_dl_h

2.26%

Adjust Power

l_rxlev_ul_ihl_rxlev_dl_ih

Quality

Interference

Sheet2

Frame 24Frame 25Idle FrameFrame 0

012345670123456701234567012

012345670123456701234567012

Frame 24Frame 25Idle FrameFrame 0

12345

Inteference on idle channel measured on Idle Timeslot by BSS

Inteference on idle channel measured on Idle Timeslot by BSS

01234567

01234567

Measurement report sent every 480ms

1st MR2nd MR3rd MR4th MR5th MR6th MR

1

2

3

1

2

1

2

1

2

3

4

5

UPLINK CELL1

UPLINK CELL2

Average

Average

Average

Average

Sheet3

MS

MSC

BSS

HLR

RACH

Imme. Assign

Location update request

Authentication request

Authentication response

DTI

DTI

Cipher mode command

Cipher mode complete

Location update accepted

VLR

MBD000DB54C.bin

MBD00060A22.doc

Page *MSC should always know the location of the MS so that it can contact it by sending pages whenever required.The mobile keeps on informing the MSC about its current location area or whenever it changes from one LA to another.This process of informing the MSC is known as location updating.The new LA is updated in the VLR.LAI = MCC + MNC + LACMCCMNCLAC3 digits1-2 digitsMax 16 bitsMCC = Mobile country code.MNC = Mobile Network Code.LAC = Location area code. Identifies a location area within a GSM PLMN network. The maximum length of LAC is 16 bits. Thus 65536 different LA can be defined in one GSM PLMN.Location Update

Page *

The communication between the base station and mobile station in mobile systems is mostly non-LOS.The LOS path between the transmitter and the receiver is affected by terrain and obstructed by buildings and other objects.The mobile station is also moving in different directions at different speeds.The RF signal from the transmitter is scattered by reflection and diffraction and reaches the receiver through many non-LOS paths.What is Fading?Signal Power (dBm)Large scale fading componentSmall scale fadingcomponent

Page *

This phenomenon is due to multipath propagation of the signal.The Raleigh fading is applicable to obstructed propagation paths. All the signals are NLOS signals and there is no dominant direct path.Signals from all paths have comparable signal strengths.The instantaneous received power seen by a moving antenna becomes a random variable depending on the location of the antenna.

Rayleigh fading

Page *General packet radio service-GPRSThe first phase of GSM network architecture enhancements that allow mobiles to connect to IP or X.25 networks.Characteristics of GPRS:Packet-switchedData rate: 9Kbps ~ 150KbpsNew functionalities: point-to-point data transferring, routing, logical link management, radio resource managementModulation: GMSK

Page *GSM Development Evolution

THANK YOU

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